This thesis deals with tones in Kanchanaburi Thai spoken at Amphoe Phanom Tuan, Amphoe Tha Muang, Amphoe Dan Makhan Tia and Amphoe Huai Krajao. The aim is to compare both the tonal systems and the phonetic characteristics of the varieties spoken in these four amphoes. Twelve informants selected according to a set of criteria were interviewed, three from each amphoe. One informant was then selected to represent each amphoe. The data contain two types of words. 1) words from a tone-set wordlist consisting of 10 items: /kaaA2, khaaA4, khaaB1, khaaC1, khaaC4, khaaA1, khaatDL1, khaatDL4, khatDS1, khatDS4/. Ten tokens were elicited for each word; 2) monosyllabic and disyllabic words from connected speech. The connected speech used in this thesis was recoded during conversation between the informants and the researcher. World selection was based on a set of criteria. Fundamental frequency value of each syllable was analyzed using the program WinCECIL and the results were processed using Excel Version 5. The studyshows that the varieties of Kanchanaburi Thai spoken at Amphoe Phanom Tuan, Amphoe Tha Muang, Amphoe Dan Makham Tia and Amphoe Huai Krajao have the same tone system consisting of five tones like Standard Thai. However, the split and merge pattern of the tone box in Kanchanaburi Thai differs from both Standard Thai and the other Central Thai accents. This study also shows that the phonetics characterestics of the tones could differentiate the four varieties of Kanchanaburi Thai. In addition, the shape and the pitch level of the tones differ when occurring in different contexts. They are most distinct in the tone-set wordlist. Their distinction decreases in connected speech. Moreover, the tones in stressed syllables are more distinct than those in unstressed syllables.
